Automatic train-control system



Oct. 8, 1929. css. BUSHNELL 3 ,842

AUTOMATIC 'TRAIN CONTROL SYSTEM OriginaLFiled May 18 1921- 2 Sheets-Sheet 1 rehrded min-Limb r l l l ATTORNEY I Oct. 8, 1929. c. s. BUSHNELL 1,730,342

AUTOMATIC TRAIN CONTROL SYSTEM )riginal Filed May 18, 1921 2 Sheets-Sheet 2 5&4.

ATORNEY i i E CHARLES S. BUSHNELL, OF ROCHESTER, NEW YORK, ASEiIGNOB TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK AUTOMATIC TRAIN-CONTROL SYSTEM Original application filed May 18, 1921, Serial No. 470,592. Divided and this application-filed February 25, 1927. Serial No. 170,846.

[El 470,592 filed May 18, 1921.

l/Vhen a system of automatic train control is applied to a train, there is a natural tendency for the engineer to rely upon this system. If the engineer has confidence in the proper performance of the automatic apparatus, he may perhaps be more lax in his observance of the usual block signals, since he will feel that theautomatic devices will in some way give a special warning or apply the brakes automatically in case of danger. It is considered objectionable, however, to take away the vigilance of the engineer, because modern block signal systems are very reliable and eliicient, and engineers as a rule are highly trained, experienced and careful operators, so that if the engineer becomes negligent in observing the signal indications or in acting upon them, there is sacrificed a large proportion of the safetyof train operation at present obtained by the signal system and the care with which the engineers ordinarily observe and obey the signals. It is evident that the ultimate safety of the train is increased if the automatic train control system is supplementary to the block signal system and the vigilance of the engineer, rather than as a substitute therefor; and if the engineer can be encouraged or forced to observe .and act upon the indications of the trackway signals, a serious accident can result only when signal system, the engineer, and the train control apparatus all fail at the same time.

lVith these considerations in mind, one object of the present invention is to provide a system of automatic train control in which a suitable penalty is automatically enforced if the engineer fails to observe a caution or stop signal, and fails to take some appropriate action in recognition of such unfavorable signal indication. If the engineer observes this indication and acts accordingly, the penalty will not be enforced and the engineer is thus encouraged to observe and act upon the signal indications. According to the present invention the penalty in question consists in causing an automatic brake application, or in imposing some suitable form of control, which persists until a reset device, is manually operated. This reset device is preferably made accessible only from the ground or is arranged in some other way so that it can not be used without great trouble and annoyance, and is also protected so that it can not be maliciously fastened down, or manipulated in such a Way as to avoid the penalty and defeat the purpose of the invention.

This invention is in the nature of an improvement upon the system disclosed and claimed in the application of W. K. Howe, Ser. N o. 7,110, filed July 30, 1925; and the patent to Howe No. 1,551,515 dated August 25,1925.

In the accompanying drawings;

Fig. 1 is a diagrammatic view of one arrangement of traokway circuits applicable to the present invention;

Fig. 2 is a diagrammatic View of a car equipment, the parts and circuits being sh own more particularly withthe object of making the functions and mode of operation easy to understand, than with the idea of showing the precise construction and arrangement of parts preferably employed in practice:

Figs. 3 to 5 inclusive, illustrate modified wiring arrangements and constructions of the car equipment.

Referring to Fig. 1, the track rails 1 of the railroad track are divided by insulated .joints 2 into blocks in the usual way, one

block N with the adjacent. ends of two other blocks M and 0 being shown. The parts and circuits associated with the several blocks are the same, and for convenience these will be given like reference characters with distinctive exponents. Each block is provided with the well-known normally closed track circuit commonly used in block signal systems, comprising a track battery 3 and a track relay 4. The usual traclrway fixed signals S are illustrated conventionally,and sincethey may take various forms, such as semaphore signals or color light signals, and may be controlled in any of the well-known ways, no

attempt has heen made to illustrate their control circuits and devices, it being understood that these signals will give the usual clear, caution, and stop indications and will be obeyed in accordance with the rules in force on the particular railroad.

In the particular embodiment of the invention illustrated, it is assumed that the transmission or communication of the desired controlling impulses or influences .irom the trackway to the moving trains for govern the automatic apparatus thereon in accordance with traiiic conditions, is accomplished inductively, that is, through an intervening air gap. While this inductive type oi impulse transmitting means may take anv one oivarious well-known forms, there is illustrated an arrangement.comprising a track element 1.

Zlhe ,track element 1 comprises in general a Usshaped yoke or core 5 of magnetic material, with coils ,6 thereon. T he cells 6 are wound and connected inseries in such a way that the cleetro-motiye,-forces generated in the respective coils by flux passing through the yoke ,5 are cumulative or additive. These track elements T may be located and controlled in various ways, dependent upon traliic conditions ,ahead, but ,in the particular arrangement shown Fig. 1, a track element T is locatec ,at the entrance to each block, a short distance in the rear of the insulated joints 2, the normal direction of tra iiic being from left. to right, as indicated by the arrow; The coils G or this ,track element are connected in series .a no anally closed circuit of low resistance, including the front contact of a line relay D. The energizing circuit to 1. ,.e line relay 1) includes a front contact of the track relay at of the corresponding blo and a front contact of the track relay thebnext ,block advance. Thais, the coils 6 of the track element T at the entrance to a given block are in a ,Closed circuit under clear traiiic conditions, but are open-circuited under caution or stop conditions, that is, when the corresponding block or the next block in advance is occu iiedf These track elements T may be located crosswise oi the track betw the track rails as shown, or lengthwise, b "c n. or outside of either track rail, d in other ways, provided the car element s disposed accordingly.

The car element Y, see .2, comprises a similar U-shaped core or yoke 7 of ma netic 'ia'crial and is supported in some suitable manner from the frame oi the locomotive or other vehicle, as to pass directly over the track element The air gap between tlie pole pieces of the track element T and the car element Y is preferably made as short as em. pniont and roadway clearances will per- Qn one leg of the yoke 7 a coil 8, conveniently termed the primary coil, and

on the other leg said yoke is another coil 9, conveniently termed the secondary coil.

In connection with the car element Y, there is preferably employed an electron ampli'l'y ing relay of the thermionic or vacuum bulb type, commonly known as an audion, and which will be referred to by that name as a matter of convenience. This audion, being well-known in the art, is illustrated conventionally, and comprises a filament F, a grid G and a plate P.

The audion controls a car relay R. The features o1 construction of this relay R, adapting it for use in a train control system or H type shown forms no part of the present invention, and this relay is shown conventionally.

The train control apparatus, which acts to apply the bmkes or in some other way govern the train with safety, may take various forms, an d since its particularconstruction forms no part ojfthe present invention, this apparatus has beet illustrated conventionally as a device This device, shown in the form of an elec ro pneumatic valve, may act to vent the train pipe and apply the brakesdirectly, or govern the operation of some other form of speed regulating or brake controlling mechanism. This device K is normally energized, and is set into operation when dc energized.

In connection with certain forms of the invention, as in Fig. 3 it is necessary to provide the device K with contacts which a... broken when said device is tie-energized. In the conventional construction illustrated, the core or plunger of the device K carries an insulated disc 10 which engages suitable fixed contacts (shown conventionally as arrows) and thus completes a circuit through said contacts when the device K is energized. lVhen the device I; is (lo-energized, its core or plunger is moved by a spring, air pressure or the like, to move the disc 10 out oi engagement with its cooperating fixed contacts. thereby breaking the circuit through said contacts.

The resetswitch or button .Q, is shown conventionally as spring plate or key 11 which normally engages a fixed Contact and can be moved from engagement therewith against another contact. This reset switch Qis in practice enclosed in a suitable protecting casing, which may be sealed or locked, or placed so as to be accessible only from the ouud. o; .u some other way arranged so that it can not be operated by the cngmcer without bringing the train to a stop, or without a great in o nvenionce, or without calling in the asance of someone else, the purpose being to make the operation of this re t; switch so objectionable to the engineer that he will voluntarily observe and obey the signals to avoid the necessity of such operation.

The hold-off switch or device H is arranged in the cab in a convenient position to be operated by the engineer. The function of this hold-off device H is to close certain contacts, when it is operated by the engineer; and to prevent its improper manipulation, there is provided associated n'iechanism which prevents the device being held closed or fastened down. A hold-oil device of this character is disclosed in a generic tl'orm in the Howe application above mentioned, and it is to be understood that no claim is made here to the generic form of the invention disclosed in the said application.

The circuit connections between the audion, the relay It, and the control device K are subject to considerable modification in practice, but since any form of connections suitable for causing operation of the relay B when the car passes an active track elcment, is applicable to the present invention, only one typical. arrangement has been illustrated. The filament F of the audion is heated by the battery 1. The grid G is connected in circuit with the secondary coil 9 and the battery C by wires 38 and 39, so that elcctroanotive-forces induced in the secondary coil will vary the grid potential. The plate P is connected in circuit with the relay 1, a front contact thereof, and the batteries 13 and C. Referring to Fig. 2 this plate circuit may be conveniently traced as follows z connnencing at the positive terminal of battery :3, wires it) and 42, front contact 43 of relay ll, wires 14 and 45, relay R, and wire 41:6 to plate P.

The primary coil 8 is normally energized "from batteries B and C through the train control device K and the front contact ll of the relay It, this circuit being traced as follows :co1n1nenciug at battery B, wires so and 42, front contact 43 of relay It, wires a l and 4:7, reset switch 11 and its closed contact, wire 48, device K, wire all), normally closed contacts 52526 primary coil 8, and wire 51 to the battery C.

()peraiz'rm-lliic battery C normally produces a positive potential upon the grid G with respect to the average potential ol the lilainent F, and. ti us permits current to flow in the plate circuit and maintain relay Pt energized. The current through the primary coil 8 produces a n1agneto-niotivc-ttorce tending to send flux through the car yoke 7, this tho: passing in part through the legs of said yoke and in part through leakage paths. The yoke 7 may be said to constitute a partial magnetic circuit with an air gap of relatively high. reluctance.

Assume that the car passes over a track elementT having its coils b open circuited, corresponding to dangerous traihc conditions ahead. that is, when a stopping impulse should be transmitted. The track element in this condition presents in effect a magnetic loop for the yoke 7 on the passing ear, and acts to complete the partial magnetic circuit on the car and change its reluctance, the reluctance decreasing from a normal to a minimum, and then back to normal, as thecar appreaches and recedes from the track element. This change in reluctance varies the flux pas through the secondary coil 9, thereby inducing an elcctro-motive-torce in said coil, first in one direction and then in the other. One half of this wave of induced E. M. F. in the secondary coil 9, either the first or the second half depending upon the connections, opposes the voltage of the battery C and reduces the potential on the grid G. The normal potential on the grid G being thus decreased, the current flowing in the plate circuit through the relay R is likewise decreased, and the parts are so proportioned and adpisted that the current in the relay R is reduced in this way below the amount required to hold its -front contact 4:?) closed. When the front contact 43 opens, the train control device K is de-energized, and the circuit through relay R is also broken atits contact 4-3, with the result that said relay can not again pickup when the grid potential again becomes normal.

Suppose that the coils 6 of the track element T are included in a closed circuit of low resistance, corresponding to clear trafic condi tions. vVhen the car element Y passes over a track element in this clear or inactive condltion, the relay R is not operated, because the coils 6 on the track element oppose or choke closed and claimed in other applications. Ar-' rangements to prevent improper operation of the car equipment by track rails or other masses of iron along the track, and various other eXpedients that may be necessary or desirable in a complete system, are not material to the present invention, and being fully disdisclosed in other applications, are not herein illustrated. Further, theoperation so .far described does not take into consideration the action of the hold-off device H, the reset switch Q, and associated parts constituting the subject-matter of thepresent invention.

As previously explained, the purpose of the present invention is to provide an arrangement for enforcing vigilance on the part of the engineer in observing and acting upon the indications of the fixed signals. The engineer is supposed to watch out for the various fixed signals S, and if one of these signals indicates caution, it is intended that he should operate the hold-off device H While passing he corresponding track element T, this act being in recognition of the cautionary indica tion of the signal and an acknowledgment that there is another train a short d ance ahead. the engineer It is assumed that ll makes such a positive movement, he fully up prociates the existence of danger and may be iclied upon to slow down the train or take "ucl action as is necessary to avoid a collision. Gonscquent y, if the engineer is alert and operates the hold-oil device at the proper time in recognition of a caution signal, it is unnecesst ry to take the control of the train out of his hands or apply the brakes at once; and the preferable arrangement of circuits is such that timely operation of the hold-off dev e H prevents, in some of the ways herev described, the effective action of the rt upon the train control device K. engineer is not a ert, however, and due to neg gence or any other cause fails to see or read correctly the signal indications, he will not operate the hold-oil device at the proper time, and then the train control appaatus K will be automatically set into operation as the train passes over the active track element, thereby slowing down the train and avoiding a collision. Further, the construction is such that the control exerted by said apparatus upon the train will be maintained until the reset switch Q is operated. If this reset switch Q is accessible only from the ground, so that the train must be stopped before it can be actuated, or it operation of this switch is made ditlicult or objectionable in some other way, the engineer will naturally prefer to operate the hold-oil device H in recognition of each caution signal, rather than be subjected to the special trouble, anno -rance. or publicity of actuating the reset switch Q. It may be noted here that the penalty, being self-inflicted, so to speak, and concurrent with the default, will naturally have more influence than any subsequent dis- I cipline, although it is evident that a recorder or similar device may be used in conjunction with the system shown and described to provide a check upon the way in which the engineer performs his duties.

ierring now to the specific arrangement of circuits and devices for preventinn' et'fective action oi? an active track element upon the train control device K when the hold-oil device H is properly operated, and for imposing a penalty when such device is not properly operated, Fig. 2 shows an arrangement in which the timely and'proper operation of the hold-oft .1 ice H, prevents dropping oil the relay R. This is done by providing connections, comprising wires 5758, which cause the secondary coil 9 to be shunted when the contacts 161S of the hold-ofi device are closed. This maintains the potential on the grid G, and prevents de-cnergization of relay R, irrcspective of the voltage changes in the secondary coil. To check the hold-oil device H against improper operation, its normally closed contacts 2526 may be included in the energizing circuit of the apparatus K as shown in Figs. 2 and 3, or in the stick circuit tor the relay 1 as shown in Fig. 5. The cam 22 is in practice biased in a clockwise direction by a force less than that exerted by the spring 15, so that this cam 22 is held in the normal position shown by the handle 12 engaging the pin 23. If however, the handle 12 is depressed by the engineer, the cam 22 is rotated in a clockwise direction at a restricted rate as determined by suitable time controlled. mechanism more specifically described in the parent application.

In the modification shown in Fig. 3, provision maoe for imposing a more severe and immediate penalty for misuse of the holdctli device thanin the embodiment of the invention shown in Fig. 2. Referring to Fig. 2, it will be noted that if the engineer holds or fastens down the handle 12 too long and the contacts 25-26 open, because the cam 22 will have rotated to a position where it allows opening; of contacts 2526, the train control device K is (lo-energized; but since the engineer may re-energize the device K and proceed by merely restoring the handle 12 to the normal position shown, there is no particular penal-y imposed for such misuse of the holdotl d ice. It is noted here that the arrangement of circuits shown in Fig. 2 may under certain circumstances act to impose penalty tor the misuse of the holdofi' device, that is, require operation of the reset switch Q. When the contacts 2526 open, they break the circuit through the primary coil 8, as well through the train control device K, resulting); in a collapse of the flux produced by said primary coil, and also of that flux normally passing through the secondary coil Such collapse or change in flux through the secondary coil 9 may reduce the grid potential and cause dropping ot' the relay R, depending upon the size and proportion of the parts, the strength of the currents in the respective circuits, and the manner of connection. In this way the relay R- is dropped when the handle 12 is held down too long, and consequently the resetswitch Q must be'operatcd before the :in control device K can be restored and the train proceed.

In the modification shown in Fig. 3, however, it' the handle 12 is held down too long, and the train control device K is operated, the train cannot be relieved of the control enforced by said device K until after a special resetting manipulation has been performed. Referring to Fig. 3, the normally closed energizing circuit for the train control device K is taken through its own contacts 10, said energizing circuit, commencing at the reset switch Q, being traced along Wires 48 and 59,

through contacts 10, wires 60 and 61, device K, wire 49, and thence through the contacts 26 and primary coil 8 to the battery. When the contacts 25-26 open because the handle 12 is held down too long, and the device l: is consequently tie-energized for rea sons already given, the contacts 10 operated by the device K (conveniently termed the stick contacts) make another break in the normal energizing circuit for said device, so

that it can not be re-energized by merely restoring the handle 12, and must be re-energized by another circuit.

While the restoration oi. the train control device K may be accomplished in various ways. in the arrangement oi circuits shown in Fig. 3, two push buttons or hand switches 62-62 are provided. at diiferent places on the train, one for operation by the engineer, and the other by the fireman, conductor, or other person. These push buttons 6262 which have been shown conventionally, may be located so that they are accessible only from the ground, or may be housed and locked in some suitable way, or otherwise protected, so that i they can not be operated without objectionable trouble and annoyance. It is noted here that instead of two push buttons 62-62 operated at the same time, only one push. button may be used if desired.

Each of the push buttons (32 and 62 has a normally opened contact 63 and a normally closed contact 64, the fir t being closed and the other opened simultaneously when the push button is actuated. The normally closed contacts 64-434 are included in the branch or shunt circuit for the secondary coil 9 in series with the contacts 1618, so that if either of these push buttons is held or fastened. down, the shunt circuit for the secondary coil can not be established by operating the hold-oil device H. In other words, it either oi the push buttons 62-62 is fastened down, the hold-olf device is made useless. The normally opened contacts 6363 of the push buttons are in series in a shunt circuit around the stick contacts 10 ot' the train control device K, said shunt circuit comprising wires 60 and 67, contact 63, wire 68, contact 63 and wires 69 and 59. i

The modification shown in Fig. 3 operates in the :tollowin manner. Assuming that the engineer holds down the handle 12 too long allowing contacts 2526 to open for reasons already given, and the train control device K is rendered active, then in order to restore this train control device, the engineer must first restore relay R by depressing reset push butten 11, must then return the handle 12 to the normal position shown so as to close contacts 25-26, and then the push buttons 6262 must be simultaneously actuated by the engineer and the fireman. This manipulation esthrough switches 63- 63 and the contacts 25-26. As soon as the train control device K is energized, its contacts 10 close, and the push buttons 6:2-62 may be released. In this way, the engineer is penalized for negligent or malicious misuse of the hold-off device H, the severity of this penalty depending upon the annoyance and ditiiculty incident to the operation oi the push buttons (3262 One advantage of having two push buttons that have to be operated simultaneously is that the engineer must then call in the fireman or conductor to assist in getting tl e train control device restored and the train under way again, thus giving publicity to the enginecfis default. It will be evident that the push buttons 62-62 can not be maliciously fastened down, since the usefulness of the hold-oti' device H is thereby destroyed, and an operation of. the train control device K will occur at the next caution signal, requiring manipulation of the reset switch Q as well as the push buttons 6262 Also, this modified arrangement shown in Fig. 3 imposes a greater penalty for failure to make timely operation of the hold-ofi' device H, since the push buttons 6262 must be actuated in addition to the reset switch Q, thereby occasioning still more trouble and annoyance.

While the provision of contacts 10 on the train control device K in its own energizing circuit, together with the push buttons 62-62 has been shown in Fig. 3 in connection with the embodiment of the invention in which the effective action of a cautionary impulse is neutralized by the hold-oil device H by virtue of establishing a shunt for the sec ondary coil 9, the same arrangement may be used in connection with the embodiment of the invention shown in Fig. 2 and a special penalty provided in this way for misuse of the hold-off device. The adaptations of'the circuit arrangement shown in Fig. 3 to the form of the invention shown in Fig. 2 will be obvious and have not been illustrat d separatelv.

Fi g. 4 shows a modified arrangementot the tacts l6'l8 are closed, the relay B may be maintained energized independently of the decrease in current between the plate and filament of the audion by an auxiliary energizing circuit as follows: commencing at an intern'iediate tap of the battery 13, wire '70,

adjustable resistance 71, wire 72, contacts 1618, wire 73, and relay R, wires 45 and 44, front contact 43, wires 42 and 40 to the end tap of the battery B. The voltage of the sec tion of the battery B included in this circuit,

In this modified arrangement together with the resistance 71, is proportioi'ied with regard to the resistance of the audion between the plate and filament, so that the current supplied to the relay R corresponds substantially with its normal working current when governed by the audi-on.

The modified circuit arrangement shown in Fig. 4 has the same general characteristics of operation that have been described. As the engineer approaches a caution signal, he may press down the lever 12 and close contac s 16 18, thereby preventing the relay R from dropping as the car element Y passes over the t 'acl: element T in the active stop- )ing condition. If the engineer does not maize proper and timely operation oi? the hold-oil device H, the rolav ll is de-energ" and the train control device K set into op 1 tion in the regular way. litter the, relay once becomes (lo-energized, and its trout contact d3 opens, the reset switch Q must be actuated before the train control device K can be re-energized.

In the arrangement shown in Fig. e the engineer is prevented from misusing the hold-oil device H by reason of the fact that this will set the train control device K into operation.

As shown in the modified form of 5, instead of protecting the hold-oil devices H against improper manipulation in the way shown in Fig. at, its normally closer contacts 25-26 may be included in the sticl; circuit of the relay ll (see Fig. 5), whereby, it the bandle 12 is held down too long, the device K is directly tie-energized by opening oi contacts 2526 and is further Clo-energized by opening of contact 43 due to the de-energization oi relay R, which relay R remains de-energized until reset push button 11 has been depressed.

Having thus shown and described my invention, it is to be understood that my invention is not limited to the specific arrangements shown and described.

VJ hat I claim is 2- 1. In an automatic train control system, an electromagnetic brake control device on a vehicle, a relay governing said device, trafiic controlled means of the induction type for controlling the relay through an intervening air gap, and manually operable means acapted only if operated in time to prevent operation ot the relay and having a limited time of eil ective operation.

2. An automatic train control system comprising, a brake applying means acting on the usual air bra to system, automatically actuated control means for governing said brake applying means, means on the vehicle for preventing the actuation of said control means and effective only if actuated before action of said control means has been initiated, means accessible only from the ground for resetting said brake applying means to normal, and means for protecting said manually operable means against misuse including means for effecting a brake application so long as said manually operable means is not returned to its normal position.

3. In an automatic train control system for railroads having tracks divided into blocks and equipped with track circuits and trackway block signals, the combination with an inductive track impulse device near each block entrance having a control circuit and assuming its active impulse transmitting condition if the control circuit is open, means for opening said control cir cuit for each track device it the corresponding signal indicates caution or stop, of carcarried equipment comprising, a brake setting dcvice normally energized electrically and acting when deenergized to cause an automatic application of the brakes, an energizing circuit for said device, a normally energized stick relay acting when de-energized to break said energizing circuit, a stick circuit for said relay including a normally closed front contact thereoit', impulse receiving means cooperating with said track impulse device and acting during the passage of the car past a track device in its active stopping condition to reduce temporarily the flow of current in said stick circuit and tend to cause said relay to release its armature and operate said brake setting appliance, manually operable circuit controlling means conveniently accessible to the operator of the vehicle and acting when in its operated position to prevent de-energization of said stick relay by an active track impulse device, said manually operable means having normally closed contacts included in the energizing circuit for the brake setting appliance and opening automatically after a predetermined time following each operation of the manually operable means, a reset switch accessible only from the ground and having normally open contacts and normally closed contacts, said normally closed contacts of the reset switch being included in said energizing circuit for the brake setting appliance, and said normally open contacts of the reset switch closing a shunt around said front contact of said stick relay and thereby permitting re-energization thereof.

4-. In an automatic train control system, the combination with a car-carried stick relay, of impulse transmitting means partly on the car and partly on the track cooperating magnetically without physical contact to reduce the current temporarily in the stick circuit of said relay and tend to cause retraction of the armature of said relay, the armature of said relay when once retracted by the action ot said impulse transmitting means remaining in the retracted position until otherwise restored, a normally energized electro-pneumatic valve tie-energized upon retraction of said armature and acting to produce an automatic brake application, a manually operable acknowledging device conveniently accessible to the operator of the vehicle and acting in the operated position to prevent retraction of the armature of said stick relay if then in its attracted position, said acknowledging device acting automatically to tie-energize said electro-magnctic valve and cause an automatic brake application it kept in its operated condition longer than a predetermined interval of time, a reset switch accessible only from the ,c ground and operable to establish a shunt around the stick contacts of said relay and permit attraction of its armature after retraction thereof, said reset switch while in its operated position maintaining said electro-magnetic valve tie-energized.

i. In an automatic train control system, car equipment adapted to apply the brakes of the car automatically upon transmission of a stopping influence from the trackway unless the operator of the car performs an anticipatory acknowledging act, comprising, a normally energized stick relay, means included in the stick circuit of said relay and responding to control influences from the trackway and tending to tie-energize said relay, a manually operable acknowledging device acting in its operated condition to render said means ineffective and thereby prevent de-energization of said stick relay, a normally inactive brake control device tending to assume its active condition and to cause an automatic brake application, a normally energized circuit for said brake control device opened upon de-energi zation of said stick relay, time controlled means for independently opening said ene"- gizing circuit after a predetermined time interval following each operation of said acknowledging device, said time controlled means being automatically restored to normal when said acknowledging device returns to normal, and reset means manually operable only after the car is stopped. to re-energize said stick relay, said reset means opening said energizing circuit for the brake control device while in its operated position.

6. In an automatic train control systm of the type described, the combination with a normally energized electro-magnetic valve on a vehicle automatically iausing a brake application upon its de-energization, an energizing circuit for said valve, means temporarily influenced from the trackway through an air gap and without physical contact for interrupting said energizing circuit, said means when once operated to break said energizing circuit remaining in that operated condition until manually restored, an ackhowledging device on the Vehicle conveniently located for manual operation by the engineer and acting when operated to maintain said means inactive but being incapable of restoring said means once it has assumed its active condition, time controlled means governed by said acknowledging device and acting automatically to apply the brakes it said device is kept in its operated position longer than a predetermined time, and resetting means manually operable only after the vehicle has come to a stop for restoring said means to normal, said resetting means while in the operated position maintaining said valve die-energized.

7. In a train control system, cooperating rack and car-carried elements, a device for applying the car brakes when initiated, electrically operated stick controllin means "for initiating said device and normally affected by trackway influences to initiate said device, and aoknowled 'ing means operable to prevent the said atlecting of the controlling means by said trackway influences, said ac knowledging means including means automatically operable after a predetermined time interval from operation of the acknowledging means, to cause initiation of said device, and resetmeans, when operated, initiating said d vice and closing a pick up circuit for said stick controlling means.

8. Gar-carried apparatus for automatic train control systems of the type in which control influences are transmitted upon passage of the vehicle by control points under adverse trahic conditions ahead, comprising a stick relay having a stick contact closed when said relay is energized; a source of energy; a circuit for energizing said relay normally closed and including in series the winding of said stick relay, said stick contact, said source o'l energy and an impulse device responsive to control influences transmitted from the trackway; said device effecting de-energization of said relay upon passage of the vehi le by a control point under adverse tra'l'lic conditions ahead; an electrically o )e'rated valve ene vehicle; and a manually operable acknowledging switch having normally closed contacts included in the energizing circuit of said valve and normally open contacts which if closed render said impulse receiving device-inefiective, said normally closed contacts remaining closed only for a limited period of time after each operation of said switch.

9. Car-carried apparatus for automatic train control systems of the type in which con rol influences are transmitted upon passage of the vehicle by control pointsunder adverse tra'fiic conditions ahead; the combination of a stick relay having a stick contact closed when said relay assumes its energized position; a sourcecr" energy; a circuit for energizing said relay normally closed and including in series the winding of said stick relay, said stick contact, said source of enorgy and device responsive to control influences t 'ansmitted from the trackway, said device effecting de-energization of said re lay upon passage oi the vehicle by a control point under adverse tralfic conditions ahead; an electrically operated valve energized by a circuit includin a front contact of said relay which valve is normally energized and which if de-energized elleots an application of the air brakes oi the vehicle; manually operable acknowledging means which it operated snunts an essential portion of said de vice so as to make this device ineffective; and manually operable restoring means for the reiay.

l0. Car-car ied apparatus for automatic train control systems of the type in which control influences are transmitted upon passage of the vehicle by control points under adverse traiiic conditions ahead comprising, a stick relay having a stick contact closed when said relay is energized; a source of en ergy; a circuit. for energizing said 'clay normally closed and including the winding of said stick relay, said stick contact, said source of energy and a device responsive to control influences transmitted from the trackway, in series; said device ei'l ecting de-energization or said relay upon passage of the vehicle by a control point under adverse tral'fic conditions ahead; an electrically opera ed valve energized by a circuit including a front contact of said relay which valve is normally energized and which it Clo-energized ellects an application of the air brakes O'i the vehicle; manually operable aeknowledgin means which it operated shunts an essential portion of said device so as to make this device ineffective; and manually operable restoring means accessible only tr m the ground having normally closed contacts contained in the enercircuit of said valve and having normally open contacts which it closed shunt the stick contact of said stick relay; said rostoring means being onstruct ;l so that it operated to its abnormal position the normally open contacts are closed and the normally closed contacts open, whereby it said restoring means is left in its operated position the brakes are maintained applied.

11. Car-carried apparatus for automatic train. control systems ot the type in which control influences are transmitted upon passage of the vehicle by control points under adverse tratlic conditions ahead; the combination of a stick relay having a stick contact closed when said relay assumes its energized position; a source of energy; a circui for energizing said relay normally closed and including the winding of said stick relay, said stick contact, said source or" energy and a device responsive to control influences transmitted from the trackway, in series; said device ellecting de-ener ization of said relay upon passage 01" the vehicle by a control point under adverse trafiic conditions ahead; an electrically operated valve energized by a ci 'cuit including a front contact of said relay which valve is normally energized and which if (lo-energized affects an application of the air brakes of the vehicle; and manually operable rcstoring means accessible only from the ground having normally closed contacts contained in the energizing circuit of said valve and having normally open contacts which it closed shunt the stick contact of said stick relay, said restoring means being constructed so that it operated to its abnormal position the normally open contacts are closed and the normally closed contacts are opened, whereby it said restoring means is left in its operated position the braks are maintained applied. 12. Car-carried apparatus for automatic train control systems comprising; a stick relay having a stick contact closed when said relav is in its energized position; a source of energy; a circuit for energizing said stick relay including a stick contact, the Winding of paid relay, said source of energy, and a device responsive to control influences transfrom the trackway and in response reduces the current flow in said circuit, in series; and an electro-pneumatic valve normally energized by a circuit including cent-a ct on said relay closed when said relay is in its energized condition and a source oi energy; and manually operable restoring means accessible only from the ground for restoring said relay and electro-pneumatic valve to normal; said restoring means including normally closed contacts contained in the energizing circuit of the elect-ro-pneumat-i0 valve and normally open contacts which it closed shunt the stick contact of said stick relay, said restoring means being constructed so that it operated to its abnormal position the normally open contacts are closed and the normally closed contacts are opened, whereby said restoring means is protected against being left in its operated position permanently.

In testin'iony whereofv I atlir: my sins iturc.

CHARLES BUSHNELL. 

